Malignant mesothelioma from neighborhood exposure to anthophyllite asbestos

BACKGROUND: Anthophyllite asbestos has been reported to cause asbestosis, lung cancer, mesothelioma, and pleural plaques in occupationally exposed workers. Anthophyllite has also been associated with pleural plaques in Finland and Japan among those who live near mines and mills and have neighborhood or environmental exposure. METHODS: We evaluated a 38-year-old patient with pleural mesothelioma who lived, attended school, and delivered newspapers near a manufacturing facility that used exclusively anthophyllite asbestos fiber from ages 8-17 years. He had no work exposure to asbestos. RESULTS: The pleural mesothelioma was an epithelial type with tubulopapillary structures and was treated with an extrapleural pneumonectomy followed by radiation therapy. The malignant cells were positive by immunohistochemistry for cytokeratin but negative for carcinoembryonic antigen, S100, B72.3, and leu M1 antigen. Anthophyllite fibers were > 5 microm in length in lung tissue compared to 3 microm from a general population study. CONCLUSIONS: Anthophyllite asbestos has been associated with neighborhood environmental exposure and pleural plaques; we now report a neighborhood exposure and pleural mesothelioma.     

Risk of developing mesothelioma due to neighborhood exposure to asbestos]

Routes of asbestos exposure consist of occupational and non-occupational exposures, and furthermore the latter is classified as para-occupational, neighborhood or true general environmental exposure. Consequently, in order to evaluate health risk caused by neighborhood exposure to asbestos, it is necessary to exclude risk due to the other exposure routes from overall risk. We reviewed epidemiological studies on the relationship between neighborhood asbestos exposure and risk of mesothelioma. In studies on a crocidolite mine in South Africa and a chrysotile mine in Canada, occupational exposure was not excluded. In studies on a crocidolite mine in Australia and an asbestos manufacturing factory in U.S.A., risk caused by non-occupational exposure was evaluated, but the risk was not classified as para-occupational and neighborhood exposures. In a study on an asbestos cement factory in Italy, first, occupational and para-occupational exposures were excluded, and next, the incidence rate of mesothelioma in neighborhood residents was calculated, so that risk caused by neighborhood exposure could be evaluated. In case-control studies in Italy, South Africa, three European countries and the U.K., risks caused by occupational, para-occupational and neighborhood exposures were evaluated separately. As a whole, relative risk (RR) of neighborhood exposure in crocidolite and amosite mines was about 10 to 30 and RR in major asbestos factories was about 5 to 20. On the other hand, statistically significant RR of neighborhood exposure was not observed in chrysotile mines and some asbestos facilities.     

Increased risk of malignant mesothelioma of the pleura after residential or domestic exposure to asbestos: a case-control study in Casale Monferrato, Italy.

The association of malignant mesothelioma (MM) and nonoccupational asbestos exposure is currently debated. Our study investigates environmental and domestic asbestos exposure in the city where the largest Italian asbestos cement (AC) factory was located. This population-based case-control study included pleural MM (histologically diagnosed) incidents in the area in 1987-1993, matched by age and sex to two controls (four if younger than 60). Diagnoses were confirmed by a panel of five pathologists. We interviewed 102 cases and 273 controls in 1993-1995, out of 116 and 330 eligible subjects. Information was checked and completed on the basis of factory and Town Office files. We adjusted analyses for occupational exposure in the AC industry. In the town there were no other relevant industrial sources of asbestos exposure. Twenty-three cases and 20 controls lived with an AC worker [odds ratio (OR) = 4.5; 95% confidence interval (CI), 1.8-11.1)]. The risk was higher for the offspring of AC workers (OR = 7.4; 95% CI, 1.9-28.1). Subjects attending grammar school in Casale also showed an increased risk (OR = 3.3; 95% CI, 1.4-7.7). Living in Casale was associated with a very high risk (after selecting out AC workers: OR = 20.6; 95% CI, 6.2-68.6), with spatial trend with increasing distance from the AC factory. The present work confirms the association of environmental asbestos exposure and pleural MM, controlling for other sources of asbestos exposure, and suggests that environmental exposure caused a greater risk than domestic exposure.     

Environmental exposure to asbestos in the area around Goor has been established as the cause of pleural mesothelioma in women

OBJECTIVE: To determine whether a disease cluster of 22 additional cases of pleural mesothelioma among women could be attributed to environmental asbestos exposure due to asbestos fibers from waste material on roads and property yards. The women studied were observed in an area with substantial environmental exposure to asbestos during the period 1989-2002. DESIGN: Ecological study. METHOD: In the study period of 1989-2002, all cases of mesothelioma among women, based on a strict histopathologic definition, occurring in the region of Twente, The Netherlands (n = 59) were provided by the regional cancer register. Additional information was collected on the occupational histories of the cases and their partners and addresses of residence through medical records, general practitioners, and next-of-kin. Environmental asbestos exposure was assigned to all cases that had had a long-term stay in a house in the area around Goor with demonstrated local environmental asbestos pollution and where any contact with asbestos through occupation or in the household had been excluded. RESULTS: In the risk area around Goor, out ofa total of 28 cases ofwomen with pleural mesothelioma, asbestos in the environment was found to be the only source of asbestos exposure for to women. In a further 4 women, environmental asbestos exposure was found to be the most likely cause of pleural mesothelioma. The average cumulative exposure was around 0.11 fiber/ml x exposure years. The observed extra incidence of 22 cases was attributed to the environmental exposure to asbestos in 64% (14/22) of cases. CONCLUSION: The environmental pollution to asbestos waste materials in the area around Goor was the main cause of the strongly increased incidence of pleural mesothelioma among women in this area. Taking into account an equal risk among men, the consequences of asbestos exposure in the area around Goor in the next 25 years are likely to result in 2 cases of pleural mesothelioma each year.     

Lung cancer and mesothelioma in the pleura and peritoneum among Swedish insulation workers

OBJECTIVES: To estimate the risk of cancer and death in Swedish insulation workers some years after their exposure to asbestos had stopped. One hypothesis was that the risk of lung cancer would tend to decrease some years after the exposure had ended. METHODS: In a cohort study the cancer morbidity and cause of death was investigated in 248 insulation workers and compared with the corresponding morbidity and mortality in the general population. Due to stringent regulations, exposure to asbestos of all types had almost ended in Sweden in the mid- 1970s. Through a questionnaire, surviving insulation workers were asked about their exposure to asbestos and their smoking habits. RESULTS: Between 1970 and 1994 there were 86 deaths compared with the 46.0 expected (standardised incidence ratio (SIR) 1.9; 95% confidence interval (95% CI) 1.5 to 2.3), the increase was mainly due to an increased cancer mortality. The morbidity was increased for lung cancer (11 cases v 2.5 expected (SIR 4.4; 95% CI 2.2 to 7.9)), peritoneal mesothelioma (seven cases; no expected incidence could be calculated as the occurrence is too rare in the general population), cancer in pancreas (five cases v 0.7 expected (SIR 7.1; 95% CI 2.3 to 16.7)). No cases of pleural mesothelioma were found. The risk of lung cancer did not tend to approach that of the general population after the exposure to asbestos decreased. CONCLUSIONS: In the 1980s and the early 1990s, Swedish insulation workers still have a highly increased risk of diseases related to asbestos. The attributable risk for death and cancer was about 50%. The study also confirms the previous finding that mesothelioma in insulation workers seems to be situated in the peritoneum more often than in the pleura.     

Mesothelioma and lung cancer among motor vehicle mechanics: a meta-analysis

We conducted a systematic review and analysis of the epidemiological literature that examines the risk of lung cancer and mesothelioma among motor vehicle mechanics who may have been engaged in brake repair and, thus, were potentially exposed to asbestos. All relevant studies were classified into three tiers according to their quality. Tier III (lowest quality) studies were cited for completeness, but were not included in the meta-analysis. Meta relative risks (meta-RRs) were calculated for mesothelioma and lung cancer using both fixed and random effects models for Tiers I and II, separately, followed by stratified analyses based on study design or exposure characterization (garage workers versus brake workers) and, for lung cancer studies, based on adequate adjustment for smoking. The meta-analysis for Tier I (higher quality) and Tier II (lower quality) studies of mesothelioma yielded RR estimates of 0.92 (95% CI 0.55-1.56) and 0.81 (95% CI 0.52-1.28), respectively. Further stratification according to exposure characterization did not affect the results. The meta-analysis for lung cancer produced RR estimates of 1.07 (95% CI 0.88-1.31) for Tier I and 1.17 (95% CI 1.01-1.36) for Tier II. When the lung cancer analysis was limited to studies that used adequate control for smoking, the resulting RR estimate was 1.09 (95% CI 0.92-1.28). Based on these findings, we conclude that employment as a motor vehicle mechanic does not increase the risk of developing mesothelioma. Although some studies showed a small increase in risk of lung cancer among motor vehicle mechanics, the data on balance do not support a conclusion that lung cancer risk in this occupational group is related to asbestos exposure.     

Occupational exposure and lung cancer risk in a coastal area of Northeastern Italy

Summary A case-control study of lung cancer and occupational exposure was conducted in a coastal area of Northeastern Italy where metallurgical and mechanical industries, docks and shipyards are located. Cases comprised 756 men who died of primary lung cancer in a 5-year period. Controls comprised 756 male subjects dying from other causes during the same period. Occupational exposures to lung carcinogens were assessed according to a job title-based approach, using two separate lists of industries/occupations recognized as being causally associated (list A) or suspected of being causally associated (list B) with lung cancer in humans. Exposure to asbestos was classified as absent, possible, or definite. After adjustment for cigarette smoking and place of residence, a significant association was found between lung cancer and occupations in both list A [relative risk (RR) = 2.25, 95% confidence interval (CI) = 1.68–3.03] and list B (RR = 1.33, 95% CI = 1.03–1.71). A significant excess risk was found for workers with definite exposure to asbestos as compared to those with no exposure to lung carcinogens (RR = 1.98, 95% CI = 1.42–2.75). Among occupations with recognized exposure to lung carcinogens other than asbestos, a significant excess risk for lung cancer was observed in iron and metalware workers. In occupational groups with definite exposure to asbestos, elevated risk estimates were found for shipyard workers, dockworkers, carpenters, and electricians. The combined effect of smoking and asbestos was found to be compatible with that expected under a multiplicative model. The overall population-attributable risk (ARp) for cigarette smoking was found to be 87.5%. The ARp estimate for occupations in list A was 16.0%. The estimate increased to 25.3% (95% CI = 16.2–34.4) when occupations in list B were included. The ARp estimate for possible or definite exposure to asbestos was 20.0% (95% CI = 11.5–28.5). With regard to the histologic types of lung cancer, significant associations were found between definite exposure to asbestos and squamous cell carcinoma (RR = 2.00, 95% CI = 1.28-–3.11), small cell carcinoma (RR = 2.11, 95% CI = 1.31–3.39), and adenocarcinoma (RR = 2.16, 95% CI = 1.32–3.53).     

Cancer mortality in a surveillance cohort of German males formerly exposed to asbestos

The objective of this analysis was the estimation of the cancer risks of asbestos and asbestosis in a surveillance cohort of high-exposed German workers. A group of 576 asbestos workers was selected for high-resolution computer tomography of the chest in 1993-1997. A mortality follow-up was conducted through 2007. Standardised mortality ratios (SMRs) were calculated and Poisson regression was performed to assess mesothelioma risks. A high risk was observed for pleural mesothelioma (SMR 28.10, 95% CI 15.73-46.36) that decreased after cessation of exposure (RR 0.1; 95% CI 0.0–0.6 for ≥30 vs. <30 years after last exposure). Asbestosis was a significant risk factor for mesothelioma (RR 6.0, 95% CI 2.4-14.7). Mesothelioma mortality was still in excess in former asbestos workers although decreasing after cessation of exposure. Fibrosis was associated with subsequent malignancy.     

The additional risk of malignant mesothelioma in former workers and residents of Wittenoom with benign pleural disease or asbestosis

Aims: To examine the hypothesis that people with benign pleural disease or asbestosis have an increased risk of malignant mesothelioma beyond that attributable to their degree of asbestos exposure. Methods: Former workers and residents of the crocidolite mining and milling town of Wittenoom are participating in a cancer prevention programme (n = 1988). The first plain chest radiograph taken at the time of recruitment into the cancer prevention programme was read for evidence of benign pleural disease and asbestosis, using the UICC classification. Crocidolite exposure of former workers was derived from employment records and records of dust measurements performed during the operation of the asbestos mine and mill between 1943 and 1966. Based on fibre counts, exposure for former residents was determined using duration of residence and period of residence (before and after a new mill was commissioned in 1957) and interpolation from periodic hygienic measures undertaken from personal monitors between 1966 and 1992. Cox proportional hazards modelling was used to relate benign pleural disease, asbestosis, asbestos exposure, and mesothelioma. Results: Between 1990 and 2002, there were 76 cases of mesothelioma (56 of the pleura and 20 of the peritoneum). Cases had more radiographic evidence of (all) benign pleural disease, pleural thickening, blunt/obliterated costophrenic angle, and asbestosis than non-cases. Adjusting for time since first exposure (log years), cumulative exposure (log f/ml-years), and age at the start of the programme, pleural thickening (OR = 3.1, 95% CI 1.2 to 7.6) and asbestosis (OR = 3.3, 95% CI 1.3 to 8.6) were associated with an increased risk of peritoneal mesothelioma. There was no increased risk for pleural mesothelioma. Conclusion: The presence of benign pleural disease, in particular pleural thickening, and asbestosis appears to increase the risk of mesothelioma of the peritoneum, but not of the pleura beyond that attributable to indices of asbestos exposure in this cohort of subjects exposed to crocidolite.     

Asbestos related diseases from environmental exposure to crocidolite in Da-yao,China. I. Review of exposure and epidemiological data

Background: Scattered patches of crocidolite, one form of asbestos, were found in the surface soil in the rural county of Da-yao in southwestern China. In 1983, researchers from the West China University of Medical Sciences (WCUMS) discovered that residents of two villages in Da-yao had hyperendemic pleural plaques and excessive numbers of pleural mesotheliomas.

Aims: To review and summarise epidemiological studies, along with other relevant data, and to discuss the potential contribution to environmental risk assessment.

Methods: This report is based on a review of several clinical/epidemiological studies conducted by WCUMS researchers since 1984, which included one cross sectional medical examination survey, one clinical/pathological analysis of 46 cases of mesothelioma, and three retrospective cohort mortality studies. Additional information acquired from reviewing original data first hand during a personal visit along with an interview of medical specialists from Da-yao County Hospital was also incorporated.

Results: The prevalence of pleural plaque was 20% among peasants in Da-yao over 40 years of age in the cross sectional survey. The average number of mesothelioma cases was 6.6 per year in the 1984–95 period and 22 per year in the 1996–99 period, in a population of 68 000. For those mesothelioma cases that were histology confirmed, there were 3.8 cases/year in the first period and 9 cases/year in the second. Of the 2175 peasants in this survey, 16 had asbestosis. Lung cancer deaths were significantly increased in all three cohort studies. The annual mortality rate for mesothelioma was 85 per million, 178 per million, and 365 per million for the three cohort studies, respectively. The higher exposed peasants had a fivefold increased mesothelioma mortality compared to their lower exposed counterparts. There were no cases of mesothelioma in the comparison groups where no crocidolite was known to exist in the environment. In the third cohort study, almost one of five cancer deaths (22%) was from mesothelioma. The ratio of lung cancer to mesothelioma deaths was low for all three studies (1.3, 3.0, and 1.2, respectively).

Conclusions: The observation of numerous mesothelioma cases at Da-yao was a unique finding, due mainly to their lifetime exposure to crocidolite asbestos. The finding of cases dying at a younger age and the relatively high ratio of mesothelioma cases to lung cancer could also be another unique result of lifetime environmental exposure to crocidolite asbestos. Although the commercial use of crocidolite has been officially banned since 1984, the incidence of mesothelioma has continued to show a steady increase, particularly among peasants. Since the latency of mesothelioma is approximately 30–40 years, the ban had little effect in the 1990s. The increased awareness and changes in diagnosis over time may also contribute to the increase. Furthermore, exposure to asbestos stoves and walls continued. The government implemented reduction of these exposures. However, from a public health standpoint, the most important issue is the complete avoidance of further exposure to asbestos.

     

Malignant mesothelioma: attributable risk of asbestos exposure.

OBJECTIVES--To evaluate a case-control study of malignant mesothelioma through patterns of exposure to asbestos based upon information from telephone interviews with next of kin. METHODS--Potential cases, identified from medical files and death certificates, included all people diagnosed with malignant mesothelioma and registered during 1975-1980 by the Los Angeles County Cancer Surveillance Program, the New York State Cancer Registry (excluding New York City), and 39 large Veterans Administration hospitals. Cases whose diagnosis was confirmed in a special pathology review as definite or probable mesothelioma (n = 208) were included in the analysis. Controls (n = 533) had died of other causes, excluding cancer, respiratory disease, suicide, or violence. Direct exposure to asbestos was determined from responses to three types of questions: specific queries as to any exposure to asbestos; occupational or non-vocational participation in any of nine specific activities thought to entail exposure to asbestos; and analysis of life-time work histories. Indirect exposures were assessed through residential histories and reported contact with family members exposed to asbestos. RESULTS--Among men with pleural mesothelioma the attributable risk (AR) for exposure to asbestos was 88% (95% confidence interval (95% CI) 76-95%). For men, the AR of peritoneal cancer was 58% (95% CI 20-89%). For women (both sites combined), the AR was 23% (95% CI 3-72%). The large differences in AR by sex are compatible with the explanations: a lower background incidence rate in women, lower exposure to asbestos, and greater misclassification among women. CONCLUSIONS--Most of the pleural and peritoneal mesotheliomas in the men studied were attributable to exposure to asbestos. The situation in women was less definitive.     

Mesothelioma in pet dogs associated with exposure of their owners to asbestos

Pet dogs with spontaneous mesothelioma were used to identify environmental exposures that might increase their owner's risk of asbestos-related disease. These animals share man's domicile environment, yet do not indulge in activities (e.g., smoking, working) which confound interpretation of epidemiologic studies. Eighteen histologically confirmed canine mesotheliomas were diagnosed at the Veterinary Hospital of the University of Pennsylvania, Philadelphia, from April 1977 to December 1981. Sixteen owners of cases and 32 owners of age, breed, and sex-matched controls were interviewed to determine their occupation and medical history and their dog's medical history, life style, diet, and exposure to asbestos. An asbestos-related occupation or hobby of a household member and use of flea repellents on the dog were significantly associated with mesothelioma. In addition, there was a trend indicating an increased risk of mesothelioma with an urban residence. Lung tissue from three dogs with mesothelioma and one dog with squamous cell carcinoma of the lung had higher levels of chrysotile asbestos fibers than lung tissue from control dogs. These findings indicate that well-designed epidemiological studies of spontaneous tumors in pet animals may provide insight into the role of environmental factors in human cancers and serve as a valuable sentinel model to identify environmental health hazards for humans.     

Risk assessment of lung cancer and mesothelioma in people living near asbestos-related factories in Taiwan.

Estimates from environmental risk assessments are criticized by professionals who indicate that inaccuracies occur in exposure assessment, model selection, and determination of the population at risk. In the current study, we tackled the aforementioned issues and estimated the risks of lung cancer and mesothelioma caused by airborne asbestos among individuals who lived near asbestos factories in Taiwan. We conducted 8-h full-period samplings upwind and downwind from each factory, and we used transmission-electronic microscopy (10,000x) and phase-contrast microscopy to determine asbestos concentrations in and around each factory. We estimated the numbers of residents who lived in concentric circles of 200-m, 400-m, and 600-m diameters around each factory. A dose-response model for asbestos-induced lung cancer was adopted from a summary of seven epidemiological studies. The asbestos-mesothelioma models were patterned after the first-exposure-effect models developed by Peto and Finkelstein. The data obtained from phase-contrast microscopy significantly overestimated the risk, compared with transmission-electronic microscopy. The estimates we calculated from adopting the arithmetic mean were approximately 2-fold higher than those we calculated with the geometric mean. There were relatively low concentrations of asbestos in the study areas, thus causing an absence of a significant difference in risk estimates between different models for mesothelioma. Among the more than 20,000 residents who lived near 41 asbestos factories in Taiwan, we found that the numbers of expected excess deaths from lung cancer and mesothelioma were 5 and less than 1, respectively. We concluded that in future risk assessments for ambient asbestos exposure, investigators should adopt transmission-electronic microscopy and the geometric mean estimate. Moreover, Taiwan should enhance asbestos-control programs to assure the safety of residents who live near asbestos factories.     

Environmental exposure to tremolite and respiratory cancer in New Caledonia: a case-control study

A case-control study on respiratory cancers was conducted in New Caledonia (South Pacific), where a high incidence of malignant pleural mesothelioma had been observed. The disease pattern suggested an environmental exposure to asbestos. The first results showed that, in some areas, tremolite asbestos derived from local outcroppings was used as whitewash (locally named "p?"). All cases diagnosed between 1993 and 1995 (including 15 pleural mesotheliomas, 228 lung cancers, and 23 laryngeal cancers) and 305 controls were included in the study. Detailed information on past or present use of the whitewash, residential history, smoking, diet, and occupation was collected. The risk of mesothelioma was strongly associated with the use of the whitewash (odds ratio (OR) = 40.9; 95% confidence interval (CI): 5.15, 325). All Melanesian cases had been exposed. Among Melanesian women, exposure to the whitewash was associated with an increased risk of lung cancer (OR = 4.89; 95% CI: 1.13, 21.2), and smokers exposed to po had an approximately ninefold risk (OR = 9.26; 95% CI: 1.72, 49.7) compared with women who never smoked and had never used the whitewash. In contrast, no association was noted between exposure to p? and lung cancer risk among Melanesian men, probably because of lower exposure levels. Among non-Melanesians, the numbers of exposed subjects were too small to assess the effect of exposure to po. There was no indication of elevated risks for the other cancer sites.     

Attributable risk in men in two French case-control studies on mesothelioma and asbestos

Pleural mesothelioma is a primary tumor of the pleura that is mainly due to asbestos exposure. To study the relationship between mesothelioma and occupational asbestos exposure in France, two case–control studies (A and B) were conducted. A substantial difference in the attributable risk in the population (AR_p) was observed among men: 44.5% (95% CI: [32.6–56.4]) in study A and 83.2% (95% CI: [76.8–89.6]) in study B. As different exposure assessment expert methods were used, the main objective of this work was to re-estimate the AR_p men in two case–control studies according to a common standardized exposure assessment by using a Job Exposure Matrix (JEM) and to assess the role of subjects’ selection. The initial observed AR_p difference was maintained: 36.3% (95% CI: [24.3–50.3]) in study A and 69.7% (95% CI: [51.7–83.2]) in study B. Further investigations highlighted the potential selection bias introduced in both studies, especially among controls. The AR_p could be underestimated in study A and overestimated in study B. After weighting subjects according to distribution of socio-economic status in the general population for controls and according to distribution of socio-economic status of cases registered by the French National Mesothelioma Surveillance Program, re-estimated AR_p values were 52.4% in study A and 70.2% in study B. These results provide additional information to describe the relationship between pleural mesothelioma and occupational asbestos exposure, but also confirm the importance of subjects’ recruitment in case control studies, particularly control selection.     

Cancer incidence among members of the Norwegian trade union of insulation workers

Insulation work has been described as an occupation with high exposure to asbestos. A cohort of members of the Norwegian Trade Union of Insulation Workers (n = 1116), hired between 1930 and 1975, was established. During 2002, the cohort was linked to the Cancer Registry of Norway. The standardized incidence ratio (SIR) of pleural mesothelioma was 12.9 (95% confidence interval [CI] = 6.0-24.6). Two cases with peritoneal mesotheliomas were found (SIR, 14.8; 95% CI = 1.8-53.4). The SIR of lung cancer was 3.0 (95% CI = 2.3-3.8). Four cases of lung cancer were observed among cork workers without any exposure to asbestos, but to cork dust and tar smoke (SIR, 5.3; 95% CI = 1.5-13.6). Our study showed a high risk of mesothelioma and an elevated risk of lung cancer among members of the Trade Union of Insulation Workers.     

The French National Mesothelioma Surveillance Program

Objectives

The French National Mesothelioma Surveillance Program (NMSP) was established in 1998 by the National Institute for Health Surveillance (InVS). Its objectives are to estimate the trends in mesothelioma incidence and the proportion attributable to occupational asbestos exposure, to help improve its pathology diagnosis, to assess its compensation as an occupational disease, and to contribute to research.

Methods

The NMSP records incident pleural tumours in 21 French districts that cover a population of approximately 16 million people (a quarter of the French population). A standardised procedure of pathological and clinical diagnosis ascertainment is used. Lifetime exposure to asbestos and to other factors (man made mineral fibres, ionising radiation, SV40 virus) is reconstructed, and a case‐control study was also conducted. The proportion of mesothelioma compensated as an occupational disease was assessed.

Results

Depending on the hypothesis, the estimated number of incident cases in 1998 ranged from 660 to 761 (women: 127 to 146; men: 533 to 615). Among men, the industries with the highest risks of mesothelioma are construction and ship repair, asbestos industry, and manufacture of metal construction materials; the occupations at highest risk are plumbers, pipe‐fitters, and sheet‐metal workers. The attributable risk fraction for occupational asbestos exposure in men was 83.2% (95% CI 76.8 to 89.6). The initial pathologist''s diagnosis was confirmed in 67% of cases, ruled out in 13%, and left uncertain in the others; for half of the latter, the clinical findings supported a mesothelioma diagnosis. In all, 62% applied for designation of an occupational disease, and 91% of these were receiving workers'' compensation.

Conclusions

The NMSP is a large scale epidemiological surveillance system with several original aspects, providing important information to improve the knowledge of malignant pleural mesothelioma, such as monitoring the evolution of its incidence, of high risk occupations and economic sectors, and improving pathology techniques.     

Unusually High Incidence of Malignant Pleural Mesothelioma in a Town of Eastern Sicily: An Epidemiological and Environmental Study

In a recent epidemiological study, researchers investigated mortality from malignant pleural neoplasms in Italy, and they detected some geographic clusters of cases of this disease. We found a town located in a volcanic area of eastern Sicily to be of special interest. The residents, some of whom were diagnosed with pleural mesothelioma, had never had any relevant exposure to asbestos during their professional lives. The results of an environmental survey suggested that a possible cause of asbestos exposure was the stone quarries near the town. The products of the quarries contain fibrous amphiboles, which are used widely in the local building industry. These fibrous amphiboles were identified as intermediate phases between tremolite and actinolite. Samples were collected from buildings in the town, and concentrations of amphibole fibers were evaluated. Fibrous phases were detected in 71 % of the samples, and fiber concentrations ranged from a few thousand to more than 4 × 10⁴ fibers/mg of material. In addition, we conducted a study on the mineral fiber lung burden in a pleural mesothelioma case. Many mineral fibers that were classified as the same tremolite-actinolite fibrous amphibole found in the quarries and in the building materials were detected in the lung tissue. The results suggest that the inhabitants of the town we studied had been exposed for several decades to asbestos fibers that were present in the material extracted from the local stone quarries. The material was subsequently used in the building industry, and this has caused an increased risk of pleural mesothelioma in the area.     

Occupational exposure to carcinogens and risk of lung cancer: results from The Netherlands cohort study.

OBJECTIVES: To investigate risk of lung cancers associated with common established carcinogenic occupational exposures (asbestos, paint dust, polycyclic aromatic hydrocarbons, and welding fumes) in a prospective cohort study among the general population, and to estimate the proportion of lung cancer cases attributable to these occupational exposures. METHODS: A prospective cohort study on diet, other lifestyle factors, job history, and cancer risk that started in 1986 in The Netherlands on 58,279 men, aged 55-69 years. Based on information about job history obtained from a self-administered questionnaire, case by case expert assessment was carried out to assign to each study subject a cumulative probability of occupational exposure for each carcinogenic exposure. For analysis, a case-cohort approach was used, in which the person-years at risk were estimated from a randomly selected subcohort (n = 1688). After 4.3 years of follow up, 524 lung cancer cases with complete job history were available. RESULTS: After adjustment for age, each of the other occupational exposures, and for smoking habits and intake of vitamin C, beta-carotene, and retinol, significant associations were found between risk of lung cancer and cumulative probability of occupational exposure to asbestos (relative risk (RR) highest/no exposure = 3.49, 95% confidence interval (95% CI) 1.69 to 7.18, trend P < 0.01 or paint dust (RR highest/no exposure = 2.48, 95% CI 0.88 to 6.97, trend P < 0.01). The population attributable risks (PARs) for the four exposures based on the multivariately adjusted RRs for ever exposed versus never exposed workers were calculated. The PAR of lifetime occupational exposure to asbestos was calculated to be 11.6%. CONCLUSIONS: This prospective cohort study among the general population showed that occupational exposure to asbestos or paint dust is associated with higher RRs for lung cancer. This study shows that after adjustment for smoking and diet about 11.6% of the cases of lung cancer in men is attributable to lifetime occupational exposure to asbestos.     

Unusually high incidence of malignant pleural mesothelioma in a town of eastern Sicily: an epidemiological and environmental study

In a recent epidemiological study, researchers investigated mortality from malignant pleural neoplasms in Italy, and they detected some geographic clusters of cases of this disease. We found a town located in a volcanic area of eastern Sicily to be of special interest. The residents, some of whom were diagnosed with pleural mesothelioma, had never had any relevant exposure to asbestos during their professional lives. The results of an environmental survey suggested that a possible cause of asbestos exposure was the stone quarries near the town. The products of the quarries contain fibrous amphiboles, which are used widely in the local building industry. These fibrous amphiboles were identified as intermediate phases between tremolite and actinolite. Samples were collected from buildings in the town, and concentrations of amphibole fibers were evaluated. Fibrous phases were detected in 71% of the samples, and fiber concentrations ranged from a few thousand to more than 4 x 10(4) fibers/mg of material. In addition, we conducted a study on the mineral fiber lung burden in a pleural mesothelioma case. Many mineral fibers that were classified as the same tremolite-actinolite fibrous amphibole found in the quarries and in the building materials were detected in the lung tissue. The results suggest that the inhabitants of the town we studied had been exposed for several decades to asbestos fibers that were present in the material extracted from the local stone quarries. The material was subsequently used in the building industry, and this has caused an increased risk of pleural mesothelioma in the area.